This invention relates to a new and useful group of organophosphazene polymers. More specifically, this invention relates to a new and useful group of organophosphazene polymers consisting of substantially linear chains of alternating N and P atoms, which substituents on the P atoms include at least three different fluoroalkoxy groups (the groups --OCH.sub.2 CF.sub.3, --OCH.sub.2 CF.sub.2 CF.sub.2 CF.sub.3 and --OCH.sub.2 (CF.sub.2).sub.6 CF.sub.3 being particularly preferred) and a fourth substituent containing some unsaturation to enhance the curability of the polymer, e.g. an alkenylaryloxy group such as ortho-allylphenoxy (OAP) or eugenoxy (i.e., 2-methoxy-4-allylphenoxy) being particularly preferred substituents.
The organophosphazene polymers of this invention are useful over a wide temperature range, possess excellent physical properties and exhibit outstanding stability to solvents, chemicals and water which makes them particularly useful in film and coating applications where high environmental resistance is desired. They also exhibit low volume swell when placed in contact with petroleum based fuels such as gasoline and oxygenated fuels, i.e., petroleum based fuels containing C.sub.1 to C.sub.4 alcohols such as gasohol. This renders them especially useful as hoses for the dispensing of petroleum based fuels and oxygenated fuels where excess swelling of the hose is undesirable and as seals such as gaskets and O-rings exposed to contact with such fuels.
Polyorganophosphazenes comprise a linear or cyclic chain of ##STR3## units in which the P atom is substituted with two organo groups which may be the same or different. Typical organo substituents are phenoxy, alkylphenoxy, halophenoxy, alkoxyphenoxy, alkoxy, polyalkoxy, haloalkoxy, and the like. Typical polyaryloxyphosphazenes are disclosed in U.S. Pat. No. 3,853,794 and typical polyfluoroalkoxyphosphazenes are taught in U.S. Pat. No. 3,515,688. Mixed aryloxy-fluoroalkoxy substituted polyphosphazenes are disclosed in U.S. Pat. No. 3,700,629.
Rose et al. U.S. Pat. Nos. 3,702,833 and 3,888,799 disclose polyfluoroalkoxyphosphazenes containing unsaturated aliphatic groups such as allyloxy that can be cross-linked by peroxide curing agents which are resistant to a wide range of solvents, acids and bases. Rose et al. U.S. Pat. No. 3,838,073 disclose polyfluoroalkoxyphosphazene homopolymers in which each substituent bonded to the phosphorus atoms contain 4 to 12 carbon atoms and are fully fluorinated. They are plastics with exceptional solvent and chemical resistance and are useful as coatings and films.
Kyker et al. U.S. Pat No. 3,943,088 discloses the addition of fluoroalkoxyphosphazene oils to poly(fluoroalkoxyphosphazene) materials which are capable of being cured to improve their processibility, stress/strain properties and low temperature flexibility.
Vicic et al. U.S. Pat. No. 3,945,966 mention that polyfluoroalkoxyphosphazenes containing isoeugenoxy moieties (i.e., 2-methoxy-4-propenylphenoxy) may be peroxide cured. This appears to be based on the research described in Reynard et al. "Evaluation Poly(Fluoroalkoxyphosphazene) Elastomers and Plastics," Final Report Contract No. DAAG46-73-C-0215, AMMRC CTR 74-18.
Kyker et al. U.S. 3,970,533 disclose polyfluoroalkoxyphosphazenes having some alkenylphenoxy substituents, especially ortho-allylphenoxy, which can be cured by peroxides, radiation or conventional sulfur vulcanization possessing outstanding solvent resistance, low temperature flexibility and good physical strength over a broad range of service conditions.
Cheng et al. U.S. Pat. No. 3,972,841 disclose polyphosphazene elastomers having improved low temperature properties containing non-fluorinated alkoxy groups and a small amount of unsaturated substituents on the phosphazene backbone to enhance curability.
Witner et al. U.S. Pat. No. 4,000,166 disclose phosphazene fluoroalkoxyelastomer compositions possessing enhanced processibility, low temperature flexibility and low volume swell in petroleum based hydraulic fluids consisting essentially of a fluoroalkoxyphosphazene in which all of the substituents attached to the P atoms are principally fluoroalkoxy groups and at least some unsaturated groups to effect curing and between about 1 and 20 parts of silicone gum rubber per 100 parts of fluoroelastomer blended therewith.
Dieck et al. U.S. Pat. No. 4,113,670 disclose polyaryloxyphosphazenes which have alkenylaryloxy groups (e.g., ortho-allylphenoxy, eugenoxy, etc.) which can be cured by peroxides or sulfur, and which can be used to form flexible and semirigid foams and coatings displaying good fire retardance and low smoke levels.
Cheng U.S. Pat. No. 4,116,785 discloses certain non-fluorinated alkoxy and/or aryloxy-substituted polyphosphazenes possessing outstanding low temperature flexibility and good physical strength over a broad range of service conditions which also contain olefinic substituents such as ortho-allylphenoxy groups which can be cured by conventional sulfur vulcanization or by radiation.
Cheng et al. U.S. Pat. No. 4,179,555 disclose oil-free poly(aryloxyphosphazene) copolymers containing residual amounts of P-Cl bonds which produce elastomeric characteristics in the copolymers in the absence of relatively low molecular weight polyphosphazene oils which are normally required to impart such characteristics and minor proportions of randomly distributed units containing reactive sites enabling the properties of the copolymers to be modified by cross-linking and/or curing. The copolymers may be utilized in various applications such as foams and coatings, and are particularly suited for use in wire coating formulations.
Klobucar U.S. Ser. No. 072,296now U.S. Pat. No. 4,849,494 discloses cured polyfluoroalkoxyphosphazene elastomers made from eugenoxy-substituted cyclic or linear polyfluoroalkoxyphosphazenes which possess superior physical properties compared to conventional cured elastomers made from ortho-allylphenoxy substituted polyfluoroalkoxyphosphazenes.